The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 04, 2000
Filed:
Jan. 29, 1998
Applicant:
Inventor:
Kien Van Phung, Allentown, PA (US);
Assignee:
Air Products and Chemicals, Inc., Allentown, PA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C08F / ; C08F / ; C08F / ; C08G / ; C08G / ;
U.S. Cl.
CPC ...
525 56 ; 525 61 ; 525 62 ;
Abstract
A process for making a thermally stable and substantially low yellow polyvinyl alcohol, and a process for reversing discoloration of polyvinyl alcohol. The process consists of treating polyvinyl acetate before saponification or treating polyvinyl alcohol after saponification with a small amount of a reducing phosphorus-containing compound and, optionally, a trace amount of a peroxide. This invention is particularly useful in producing low molecular weight polyvinyl alcohol which is thermally stable and low in yellow color.